Gas and oil hot water tank and Boiler Share Vents

Can a boiler and a separate hot water heater share a vent?

Pls someone. Need an opinion for a report going out today.

Any pictures?

(2003 IRC) M1801.11 Two or more listed and labeled appliances connected to a common natural draft venting system shall comply with the following.

  1. Appliances that are connected to common venting systems shall be located on the same floor.

  2. Vent inlets shall be offset so as not to be directly opposed.

  3. Connectors serving a natural draft system shall not be connected to a positive pressure system.

Connectors serving a natural draft system shall not be connected to a positive pressure system.

You stated this, does this mean a flue gas fan inducer for a newer furnace can share the same vent as a natural draft water heater? (80% furnace not a 90%)

Thank you Mr. Kelly.

Hank I have yet to see an resedidential Oil fired anything. I could be wrong in my reading of the code. Wait for a second confirming opinion.:smiley:

Hi Hank!

If at all possible, I would like a picture. I hope that his helps.

M1801.11 Multiple-appliance venting systems.
Two or more listed and labeled appliances connected to a common natural draft venting system shall comply with the following requirements:

  1. Appliances that are connected to common venting systems shall be located on the same floor of the dwelling.
    Exception: Engineered systems as provided for in Section G2427.
  2. Inlets to common venting systems shall be offset such that no portion of an inlet is opposite another inlet.
  3. Connectors serving appliances operating under a natural draft shall not be connected to any portion of a mechanical draft system operating under positive pressure.
    M1801.12 Multiple solid fuel prohibited.
    A solid fuel-burning appliance or fireplace shall not connect to a chimney passageway venting another appliance.

M1803
CHIMNEY AND VENT CONNECTORS
M1803.1 General.
Connectors shall be used to connect fuel burning appliances to a vertical chimney or vent except where the chimney or vent is attached directly to the appliance.

M1803.2 Connectors for oil and solid fuel appliances.
Connectors for oil and solid-fuel-burning appliances shall be constructed of factory-built chimney material, Type L vent material or single-wall metal pipe having resistance to corrosion and heat and thickness not less than that of galvanized steel as specified in Table M1803.2.
TABLE M1803.2 THICKNESS FOR SINGLE-WALL METAL PIPE CONNECTORS

For SI: 1 inch = 25.4 mm.
M1803.3 Installation.
Vent and chimney connectors shall be installed in accordance with the manufacturer’s installation instructions and within the space that the appliance is located. Appliances shall be located as close as practical to the vent or chimney. Connectors shall be as short and straight as possible and installed with a slope of not less than 1/4 inch (6.4 mm) rise per foot of run. Connectors shall be securely supported and joints shall be fastened with sheet metal screws or rivets. Devices that obstruct the flow of flue gases shall not be installed in a connector unless listed and labeled or approved for such installations.
M1803.3.1 Floor, ceiling and wall penetrations.
A chimney connector or vent connector shall not pass through any floor or ceiling. A chimney connector or vent connector shall not pass through a wall or partition unless the connector is listed and labeled for wall pass-through, or is routed through a device listed and labeled for wall pass-through and is installed in accordance with the conditions of its listing and label. Connectors for oil-fired appliances listed and labeled for Type L vents, passing through walls or partitions shall be in accordance with the following:

  1. Type L vent material for oil appliances shall be installed with not less than listed and labeled clearances to combustible material.
  2. Single-wall metal pipe shall be guarded by a ventilated metal thimble not less than 4 inches (102 mm) larger in diameter than the vent connector. A minimum 6 inches (152 mm) of clearance shall be maintained between the thimble and combustibles.
    M1803.3.2 Length.
    The horizontal run of an uninsulated connector to a natural draft chimney shall not exceed 75 percent of the height of the vertical portion of the chimney above the connector. The horizontal run of a listed connector to a natural draft chimney shall not exceed 100 percent of the height of the vertical portion of the chimney above the connector.
    M1803.3.3 Size.
    A connector shall not be smaller than the flue collar of the appliance.
    Exception: Where installed in accordance with the appliance manufacturer’s installation instructions.
    M1803.3.4 Clearance.
    Connectors shall be installed with clearance to combustibles as set forth in Table M1803.3.4. Reduced clearances to combustible materials shall be in accordance with Table M1306.2 and Figure M1306.1.

M1803.4.2 Connection to factory-built fireplace flue.
A different appliance shall not be connected to a flue serving a factory-built fireplace unless the appliance is specifically listed for such an installation. The connection shall be made in conformance with the appliance manufacturer’s instructions.

M1803.4.3 Connection to masonry fireplace flue.
A connector shall extend from the appliance to the flue serving a masonry fireplace such that the flue gases are conveyed directly into the flue. The connector shall be accessible or removable for inspection and cleaning of both the connector and the flue. Listed direct connection devices shall be installed in accordance with their listing.

M1804
VENTS
M1804.1 Type of vent required.
Appliances shall be provided with a listed and labeled venting system as set forth in Table M1804.1.
TABLE M1804.1
VENT SELECTION CHART

M1804.2.1 Through the roof.
Vents passing through a roof shall extend through flashing and terminate in accordance with the manufacturer’s installation requirements.
M1804.2.2 Decorative shrouds.
Decorative shrouds shall not be installed at the termination of vents except where such shrouds are listed and labeled for use with the specific venting system and are installed in accordance with the manufacturer’s installation instructions.
M1804.2.3 Natural draft appliances.
Vents for natural draft appliances shall terminate at least 5 feet (1524 mm) above the highest connected appliance outlet, and natural draft gas vents serving wall furnaces shall terminate at an elevation at least 12 feet (3658 mm) above the bottom of the furnace.
M1804.2.4 Type L vent.
Type L venting systems shall conform to UL 641. Such vents shall terminate with a listed and labeled cap in accordance with the vent manufacturer’s installation instructions not less than 2 feet (610 mm) above the roof and not less than 2 feet (610 mm) above any portion of the building within 10 feet (3048 mm).
M1804.2.5 Direct vent terminations.
Vent terminals for direct-vent appliances shall be installed in accordance with the manufacturer’s installation instructions.
M1804.2.6 Mechanical draft systems.
Mechanical draft systems shall be installed in accordance with their listing, the manufacturer’s installation instructions and, except for direct vent appliances, the following requirements:

  1. The vent terminal shall be located not less than 3 feet (914 mm) above a forced air inlet located within 10 feet (3048 mm).
  2. The vent terminal shall be located not less than 4 feet (1219 mm) below, 4 feet (1219 mm) horizontally from, or 1 foot (305 mm) above any door, window or gravity air inlet into a dwelling.
  3. The vent termination point shall not be located closer than 3 feet (914 mm) to an interior corner formed by two walls perpendicular to each other.
  4. The bottom of the vent terminal shall be located at least 12 inches (305 mm) above finished ground level.
  5. The vent termination shall not be mounted directly above or within 3 feet (914 mm) horizontally from an oil tank vent or gas meter.
  6. Power exhauster terminations shall be located not less than 10 feet (3048 mm) from lot lines and adjacent buildings.
  7. The discharge shall be directed away from the building.
    M1804.3 Installation.
    Type L and pellet vents shall be installed in accordance with the terms of their listing and label and the manufacturer’s installation instructions.
    M1804.3.1 Size of single appliance venting systems.
    An individual vent for a single appliance shall have a cross-sectional area equal to or greater than the area of the connector to the appliance, but not less than 7 square inches (4515 mm2) except where the vent is an integral part of a listed and labeled appliance.

Hank!
You have E-Mail with “charts / Graphs”